MADRID — Vicente Muñiz was 4 years old when his parents were taken away. As Members of the Marxist Worker's Unification Party (POUM), they were arrested in the closing days of the Spanish Civil War for being political enemies of Francisco Franco's victorious Nationalists. In 1941, they were found guilty, executed for their "crimes," and buried in a mass grave.

Once the dictatorship ended in 1975, Muñiz tried to clear his parents' names. He convinced the Supreme Court to review their case, but the court ruled it could do nothing, because Muñiz's parents were fairly convicted by the law then in effect.

Now, Muñiz may get another chance. Last week, the ruling Socialist Party cleared the way for passage of their proposed Law of Historical Memory by agreeing to include a provision that would declare the political trials of the 36-year Franco dictatorship "illegitimate."

The decision marks the first time a Spanish government has publicly challenged the legality of the dictatorship. While other European countries began relatively soon after the end of World War II to prosecute citizens who had carried out atrocities and make amends to their victims, Spain has resisted investigations and reparations. Instead, when Franco died in 1975, parties across the political spectrum colluded in a "pact of silence" designed to ensure a peaceful transition to representative government. While Spain quickly became a constitutional democracy, it took almost 30 years before citizens dared speak of the old regime's abuses.

"The pact of silence was necessary for the Transition," says José María Pedreña, of the Forum for Memory, an organization dedicated to identifying Republican supporters killed or missing during the war and ensuing dictatorship. "But it meant that our democracy was flawed from the beginning, because it rested on the impunity of Franco's regime."

In the 1940s, hundreds of thousands of Spaniards were arrested, tried, and in many cases summarily executed for having supported the democratically elected Republican government during the civil war. Well into the 1960s and '70s, Franco's Tribunal of Public Order punished thousands found guilty of "rebellion." With only one exception, the families of those political prisoners, many of whom lost their homes and businesses as a result of their affiliation with the persecuted, have never managed to have the sentences overturned.

The original draft of the Law of Historical Memory, which among other things provides pensions for soldiers who fought in the Republican army and requires symbols of the Franco regime to be removed from public places, was opposed by parties on the left which felt it did not go far enough. As a result, the bill languished for more than four months. Now, with the Socialists' agreement to include a provision that denies the legitimacy of Franco's political trials, the United Left (IU), and the Catalan Green Initiative (ICV) have added their support, bringing with them enough votes to pass the law.

"This is the first time that a government in Spain's democracy has recognized that not just the coup d'état [which started the Civil War that would bring Franco to power], but the regime's persecution of political opponents was against the law," says Julián Casanova, a history professor at the University of Zaragoza.

Still the Socialists have stressed that the legislation does not automatically annul previous convictions. "This is a law that neither breaks anything, nor dredges up the past," said Vice President Maria Teresa Fernández de la Vega. "It simply recognizes and extends the rights of those people whose rights were harmed during the civil war and the dictatorship."

But many are convinced that it will have a judicial impact. "Our final objective is to nullify the sentences," says a source within the leadership of the United Left party. "We agreed to the legislation because we see the term "illegitimate" as the door that opens the way to annulment."

Already the regional government of Catalonia has announced that it will offer legal support to people who want to annul their relatives' sentences.

Some worry the new provision doesn't go far enough, however. "Declaring the courts illegitimate is not the same thing as declaring them illegal," says Mr. Pedreña, who is concerned that the provision does not require old sentences to be overturned nor provide family members with indemnification. "Plus, it does nothing to punish those criminals in the Franco regime who are still young enough to be working today."

Still, many are hopeful that the Law of Historical Memory is a step in the right direction. "The great problem of the Transition was that the victors' memory of the war outweighed that of the vanquished," says Professor Canovas. "By declaring the Franco trials 'illegitimate,' the law balances the historical memory."

In the Basque town of Guernica, which is on Thursday commemorating the 70th anniversary of the town's devastating bombing by a German air-force contingent working at Franco's behest, there is hope that the new law will right some of the last century's wrongs. "For so long the winners of the civil war manipulated the truth," says Iratxe Momoitio, director of Guernica's Museum of Peace. "Anything that helps people learn what really happened is positive. With a little education, maybe those terrible events won't be repeated."